|
Chemistry Regents June 2010 - Question 27 |
 |
 |
 |
|
Written by The Chemistry Wizard
|
|
Answer: (3)
Why? There are many types of high-energy emissions known today, common types of which are alpha particles, beta particles and gamma rays. An alpha particle (represented by the Greek letter α) is the equivalent of a He2+ ion. It consists of two protons and two neutrons, this gives it both charge and mass as the protons are positively charged and the nuclide of an atom contains most of its mass.
A beta particle (represented by the Greek letter β) is a high-speed electron or positron generated by radioactive decay of unstable nuclei. As both electrons and positrons have a charge and mass (although miniscule), a beta particle would not be the correct answer.
A Gamma ray (represented by the Greek letter γ) is high-energy electromagnetic radiation. Gamma rays are produced from processes such as fission (the main process of nuclear reactors) and fusion (the reaction that powers the sun) and are composed of high-energy waves with frequencies above 1019Hz. This type of radiation is very dangerous and is sometimes referred to as penetrating radiation, as it will penetrate materials that would prevent the passage of alpha and beta particles. However gamma rays do not have mass or charge and therefore, fits the requirements of the question.
A positron, which in its simplest definition is a positively charged electron or positively charged beta particle. Therefore, a positron does have charge and mass and would not meet the requirements of the question.
Answering the Question: If an understanding of the definition of each answer was unknown, answer (1) and answer (2) are both particulate, suggesting at the very least both have mass, eliminating both as correct answers. The only possible answers would be gamma rays and positrons, if neither was known a good guess would be gamma ray simply because it is a ray, suggesting no mass and possibly no charge.
|
